Described a bit topic base class and methods.

src/Client.php

@@ -54,6 +54,13 @@ class Client implements ClientInterface {
     $this->logger = $logger;
   }
 
+  /**
+   * {@inheritDoc}
+   */
+  public function getBaseUrl(): string {
+    return $this->base_url;
+  }
+
   /**
    * {@inheritDoc}
    */
@@ -82,5 +89,4 @@ class Client implements ClientInterface {
     // TODO: Implement getTopic() method.
   }
 
-
 }

src/ClientInterface.php

@@ -4,6 +4,14 @@ namespace Toloka\PhpApi;
 
 interface ClientInterface {
 
+  /**
+   * Get Toloka base url.
+   *
+   * @return string
+   *   Absolute URL to toloka.
+   */
+  public function getBaseUrl(): string;
+
   /**
    * Login using credentials.
    *

src/Topic/TopicBase.php

@@ -2,8 +2,37 @@
 
 namespace Toloka\PhpApi;
 
-abstract class TopicBase implements TopicInterface {
+class TopicBase implements TopicInterface {
 
+  protected Client $client;
 
+  protected int $id;
+
+  public function __construct(
+    Client $client
+  ) {
+    $this->client = $client;
+  }
+
+  /**
+   * @return int
+   */
+  public function id(): int {
+    return $this->id;
+  }
+
+  /**
+   * @param int $id
+   */
+  public function setId(int $id): void {
+    $this->id = $id;
+  }
+
+  /**
+   * {@inheritDoc}
+   */
+  public function url(bool $absolute = TRUE): string {
+    return $this->client->getBaseUrl() . 't' . $this->id();
+  }
 
 }